Study On Plant Diversity, Niche And Interspecific Association Under Fencing Measures And Mowing In The Bashang Rigion

In order to find the plant community characteristics, niche pattern and interspecific association of grassland in Bashang region, two 100m×100 m enclosure fixed sampling plots in the Hongsongwa Natural Reserve was set up,and the plots studied with the quadrat method. And analysised on community characteristics, plant diversity, niche breadth, niche overlap, niche similarity, interspecific association and determined the interspecific association index. The results were as follows: 1 Enclosed measure area and continuous grazing area(1)The basic components of plant communities inside and outside the fence did not change significantly. In both areas,the dominant species were Carex lanceolata Boott, Polygonum viviparum L.,Sanguisorba officinalis L.,and Artemisia tanacetifolia L.,et al.(2)The enclosure increased vegetation height, density and above-ground biomass. The average height of the vegetation increased significantly and vegetation density increased not significantly in the enclosure.(3)The species richness index(S), dominance index(DS and H) and uniformity index(JP) of tested areas were not significant difference.(4)The niche breadth in the top three were always Sanguisorba officinalis,Polygonum viviparum and Carex lanceolata in the enclosure. However Sanguisorba officinalis,Carex lanceolata and Artemisia tanacetifolia were the top three in continuous grazing area. It showed that these plants in sample areas had strong ecological adaptability.(5)Niche overlap value of the highest in enclosure were among Sanguisorba officinalis,Polygonum viviparum,Carex lanceolata,Ranunculus japonicas and Artemisia tanacetifolia. And the highest niche overlap value in continuous grazing area were among Carex lanceolata,Artemisia tanacetifolia,Trifolium lupinaster L.,Ranunculus japonicas Thunb. and Sanguisorba officinalis. The average niche overlap value were not significant difference between the two areas, except the first year.(6)The niche proportional similarity of the highest in enclosure were among Sanguisorba officinalis, Polygonum viviparum, Carex lanceolata, and Ranunculus japonicas. And the highest niche proportional similarity in continuous grazing area were among Carex lanceolata, Artemisia tanacetifolia,Trifolium lupinaster, Ranunculus japonicas and Sanguisorba officinalis. The average niche proportional similarity were not significant difference between the two areas, except the first year.(7)Community in general were negative correlation of the first year, and positive association of the later two years in enclosure. Community in general were negative correlation of the third year, and positive association of the first and second year in continuous grazing area. Ochiai index and Dice index were mainly distributed between 0.25 to 0.5, and Jaccard index were mainly distributed between 0 to 0.25 on both tested areas. 2 Mowing plot and control plot(1)The both plots are mainly compositae, rosaceae, and gramineae and the dominant species were Carex lanceolata, Polygonum viviparum, Potentilla anserina L.,and Artemisia tanacetifolia,et al.(2)The mowing treatment reduced the above-ground biomass, and then increased biomass significantly, It showed that mowing treatment can increase the above-ground biomass once a year. The average height of the vegetation decreased not significantly and vegetation density increased not significantly in the mowing plot.(3)The species richness index(S), dominance index(DS and H) increased not significantly, and uniformity index(JP) increased significantly in mowing plot.(4)The niche breadth in the top three were Achillea asiatica Serg., Sanguisorba officinalis, Trifolium lupinaster in the mowing plot. However Sanguisorba officinalis,Ranunculus japonicus,Trifolium lupinaster and Carex lanceolata,were the top four in control plot.(5)Niche overlap value of the highest in mowing plot were among Trifolium lupinaster, Carex lanceolata, Bupleurum smithii Wolff, Sanguisorba officinalis,Ranunculus japonicas and Artemisia tanacetifolia. The highest niche overlap value in control plot were among Polygonum viviparum, Ranunculus japonicas, Artemisia integrifolia and Sanguisorba officinalis. The average niche overlap value were not significant difference between the two plots.(6)The niche proportional similarity of the highest in mowing plot were among Trifolium lupinaster, Carex lanceolata, Bupleurum smithii, Sanguisorba officinalis and Polygonum viviparum. The highest niche overlap value in control plot were among Ranunculus japonicas, Polygonum viviparum, Artemisia integrifolia L., Sanguisorba officinalis and Carex lanceolata. The average niche proportional similarity were significant difference in 2013, but significant not difference in 2014 between the two plots.(7)Community in general were significant correlation in mowing plot, in which 2013 was significant positive correlation and 2014 was significant negative correlation. In control plot, Community in general were negative correlation in 2013, and significant positive correlation in 2014. Ochiai index and Dice index were mainly distributed between 0.5 to 1, and Jaccard index were mainly distributed between 0.25 to 0.5 in mowing plot(2013 and 2014) and control plot(2013). In control plot, Ochiai index, Dice index and Jaccard index were mainly distributed between 0.5 to 1 of 2014.